U.S. patent application number 10/997672 was filed with the patent office on 2006-05-25 for by-pass valve for heat exchanger.
Invention is credited to Robert Arundine, Dario Bettio, Mark Stephen Kozdras, Jeff Sheppard, Silvio Tonellato.
Application Number | 20060108435 10/997672 |
Document ID | / |
Family ID | 36460063 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060108435 |
Kind Code |
A1 |
Kozdras; Mark Stephen ; et
al. |
May 25, 2006 |
By-pass valve for heat exchanger
Abstract
A valve that includes a housing defining first and second bores
having a central axis, and a peripheral valve seat. An actuator is
located in the first bore and has a reciprocating seal disposed for
movement along the central axis for engaging the valve seat and
closing the valve. A coiled return spring is mounted in the housing
for urging the reciprocating seal towards the chamber to open the
valve, the return spring having a first end connected to the
reciprocating seal and a second end engaging a spring support in
the housing facing the first bore. The return spring may have a
larger diameter at its second end than its first end. The housing
may include a third bore in communication with the second bore and
having a different cross-sectional area than the second bore. A
closure cap formed from moldable material may close an opening in
the housing, the closure cap being sealably joined to the housing
by a welded joint. The return spring could be supported by a
discrete spring support located in one of the bores. The valve seat
and an annular sealing member may have corresponding sloping
surfaces that cooperate when the sealing member engages the valve
seat.
Inventors: |
Kozdras; Mark Stephen;
(Fergus, CA) ; Sheppard; Jeff; (Milton, CA)
; Arundine; Robert; (Windsor, CA) ; Tonellato;
Silvio; (Mississauga, CA) ; Bettio; Dario;
(Mississauga, CA) |
Correspondence
Address: |
DYKEMA GOSSETT PLLC
39577 WOODWARD AVENUE
SUITE 300
BLOOMFIELD HILLS
MI
48304-5086
US
|
Family ID: |
36460063 |
Appl. No.: |
10/997672 |
Filed: |
November 24, 2004 |
Current U.S.
Class: |
236/93R |
Current CPC
Class: |
F28F 27/02 20130101;
Y10T 137/7922 20150401; Y10T 137/8778 20150401; F28F 2250/06
20130101; G05D 23/1333 20130101; Y10T 137/7929 20150401; Y10T
137/86726 20150401; Y10T 137/7925 20150401 |
Class at
Publication: |
236/093.00R |
International
Class: |
G05D 23/02 20060101
G05D023/02; G05D 23/08 20060101 G05D023/08 |
Claims
1. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing defining communicating first and second bores
therein, first and second main ports communicating with the first
bore, and at least a further port communicating with the second
bore, the second bore having a central axis and a peripheral valve
seat about a valve opening facing the first bore; a temperature
responsive actuator located in the housing and having a
reciprocating central shaft disposed along said central axis, the
central shaft having a closed end portion; an annular sealing
member slidably mounted on the central shaft and extending outward
from the central shaft to engage the valve seat and, together with
the closed end portion, close the valve opening; bias means for
urging the annular sealing member toward the valve seat; and a
coiled return spring mounted in the housing for urging the central
shaft closed end portion to retract and open the valve opening, the
return spring having a first end connected to the closed end
portion and a second end engaging a spring support in the housing
facing the first bore, the return spring having a larger diameter
at its second end than its first end.
2. The by-pass valve of claim 1 wherein the return spring tapers
outward from its first end to its second end.
3. The by-pass valve of claim 1 wherein coils of the return spring
have increasing diameters as the distance of the coils from the
first end increases.
4. The by-pass valve of claim 1 wherein along a first axial length
of the return spring, coils of the return spring have decreasing
diameters as the distance of the coils from the first end
increases, and along a second axial length of the return spring
that is further from the first end than the first axial length,
coils of the return spring have increasing diameters as the
distance of the coils from the first end increases.
5. The by-pass valve of claim 1 wherein the second bore and first
bore are cylindrical, the second bore having a smaller diameter
than the first bore.
6. The by-pass valve of claim 1 wherein the spring support includes
a spring seat extending at least partially about a periphery of the
second bore.
7. The by-pass valve of claim 1 wherein the housing includes a
branch port forming with the further port a branch port passage
that communicates with the second bore, the spring support being
located in the branch port passage.
8. The by-pass valve of claim 1 including a third bore serially
communicating with the second bore, the second bore communicating
directly with the first bore, the second bore having a larger
cross-sectional flow area than the third bore, wherein the spring
support includes a peripheral spring seat engaging the second end
of the return spring, the peripheral spring seat being located at a
transition between the second bore and the third bore, the second
bore communicating with the further port through the third
bore.
9. The by-pass valve of claim 8 wherein the third bore has a
non-circular cross-sectional area transverse to the central axis
and the second bore has a circular cross-sectional area transverse
to the central axis.
10. The by-pass valve of claim 1 including a closure cap, the
housing including an assembly opening located opposite the valve
seat that is sealed shut by the closure cap, the closure cap and
housing being formed from plastic materials with the closure cap
sealably joined to the housing.
11. The by-pass valve of claim 10 wherein the closure cap is joined
to the housing by ultrasonic welding, friction welding, adhesive
bonding or solvent bonding.
12. The by-pass valve of claim 1 wherein the spring support
includes a discrete support member extending across the second bore
and having a flow opening therethrough.
13. The by-pass valve of claim 1 wherein the annular sealing member
and the valve seat have sloping surfaces that cooperate when in a
closed position.
14. A valve comprising: a housing defining a first bore and a
second bore having a common central axis and communicating with
each other through a valve opening having a peripheral valve seat,
the first bore, second bore and valve opening forming at least a
portion of a closable flow path between a first opening and a
second opening in the housing; an actuator located in the housing
and having a reciprocating seal disposed for movement along the
central axis for engaging the valve seat and closing the valve
opening; a coiled return spring mounted in the housing for urging
the reciprocating seal towards the first bore to open the valve
opening, the return spring having a first end connected to the
reciprocating seal and a second end engaging a spring support in
the housing facing the first bore, the return spring having a
larger diameter at its second end than its first end.
15. The valve of claim 14 wherein the reciprocating seal includes a
reciprocating central shaft disposed along the central axis and
having a closed end portion, and an annular sealing member slidably
mounted on the central shaft and extending outward from the central
shaft to engage the valve seat and, together with the closed end
portion, close the valve opening; the actuator including bias means
for urging the annular sealing member toward the valve seat;
wherein the first end of the return spring is connected to the
closed end portion of the central shaft.
16. The valve of claim 14 wherein the return spring tapers outward
from its first end to its second end.
17. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing defining a serially communicating first bore,
second bore and third bore substantially aligned along a central
axis with a valve seat facing the first bore at a juncture between
the first bore and second bore and a spring seat facing the second
bore at a juncture between the second bore and third bore, the
first bore, second bore and third bore forming at least a portion
of a closable flow path between a first opening and a second
opening in the housing; an actuator located in the housing and
having a reciprocating seal disposed for movement along the central
axis for engaging the valve seat and closing a valve opening
between the first bore and second bore; and a coiled return spring
mounted in the housing for urging the reciprocating seal towards
the first bore to open the valve opening, the return spring having
a first end acting on the reciprocating seal and a second end
engaging the spring seat, wherein the second bore and third bore
each have a different cross-sectional shape transverse to the
central axis.
18. The by-pass valve of claim 17 wherein the second bore has a
circular cross-sectional shape and the third bore has a
non-circular cross-sectional shape.
19. The by-pass valve of claim 18 wherein the third bore has a four
sided cross-sectional shape.
20. The by-pass valve of claim 19 wherein the third bore has a
rectangular cross-sectional shape.
21. The by-pass valve of claim 17 wherein the second bore has a
larger cross-sectional flow area than the third bore and the
reciprocating seal includes a reciprocating central shaft disposed
along the central axis and having a closed end portion, and an
annular sealing member slidably mounted on the central shaft and
extending outward from the central shaft to engage the valve seat
and, together with the closed end portion, close the valve opening;
the actuator including bias means for urging the annular sealing
member toward the valve seat; and the housing defines at least two
ports communicating with the first bore and two further ports
communicating with the third bore.
22. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing formed from a plastic material and defining a
first bore with a valve opening communicating therewith, the valve
opening having a peripheral valve seat facing the first bore, the
housing defining an assembly opening communicating with the first
bore opposite the valve seat, the first bore and valve opening
forming at least a portion of a closable flow path between a first
opening and a second opening in the housing; an actuator located in
the first bore and having a reciprocating seal disposed for
movement along an axis for engaging the valve seat and closing the
valve opening; and a closure cap formed from plastic material and
closing the assembly opening, the closure cap being sealably joined
to the housing by a permanent joint.
23. The by-pass valve of claim 22 wherein the closure cap is joined
to the housing by an ultrasonic weld or a friction weld.
24. The by-pass valve of claim 22 wherein the closure cap is joined
to the housing by an adhesive bond or a solvent bond.
25. The by-pass valve of claim 22 wherein the reciprocating seal
includes a reciprocating central shaft that is driven by a piston
and disposed along a central axis of the first bore and having a
closed end portion and an annular sealing member slidably mounted
on the central shaft and extending outward from the central shaft
to engage the valve seat and, together with the closed end portion,
close the valve opening; and the actuator includes bias means for
urging the annular sealing member toward the valve seat, the
by-pass valve including a return spring within the housing for
urging the annular sealing member away from the valve seat.
26. The by-pass valve of claim 25 wherein the actuator piston is
connected to the closure cap.
27. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing defining a first bore with a valve opening
communicating therewith, the valve opening having a peripheral
valve seat facing the first bore, the housing defining an assembly
opening communicating with the first bore opposite the valve seat,
the first bore and valve opening forming at least a portion of a
closable flow path between a first opening and a second opening in
the housing; an actuator located in the first bore and having a
reciprocating seal disposed for movement along an axis for engaging
the valve seat and closing the valve opening; and a closure cap
closing the assembly opening, the closure cap being sealably joined
to the housing by a permanent joint selected from the group
consisting of a friction weld, an ultrasonic weld, a solvent bond
and an adhesive bond.
28. A method for making a by-pass valve for a heat exchanger
circuit, comprising: providing a housing defining a first bore with
a valve opening communicating therewith, the valve opening having a
peripheral valve seat facing the first bore, the housing including
an assembly opening opposite the valve seat; providing a closure
cap; providing an actuator having a reciprocating seal and
inserting the actuator into the first bore through the assembly
opening so that the actuator is located in the first bore for
movement along a central axis for engaging the valve seat and
closing the valve opening; and permanently connecting the closure
cap to the housing to seal the assembly opening.
29. The by-pass valve of claim 28 wherein the housing and closure
cap are molded from plastic materials.
30. The method of claim 29 wherein the step of permanently
connecting includes ultrasonically welding or friction welding the
housing and closure cap to each other.
31. The method of claim 29 wherein the step of permanently
connecting includes connecting the closure cap to the housing by
adhesive binding or by solvent bonding.
32. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing defining a communicating first bore and
second bore with a peripheral valve seat located at a junction
thereof about a valve opening, the first bore, second bore and
valve opening forming at least a portion of a closable flow path
between a first opening and a second opening in the housing; an
actuator located in the first bore and having a reciprocating seal
disposed for movement to engage the valve seat and close the valve
opening; a coiled return spring mounted in the housing for urging
the reciprocating seal towards the first bore to open the valve
opening, the return spring having a first end acting on the
reciprocating seal, and a second end; and a discrete spring support
extending across the second bore and having a surface supporting
the second end of the return spring, the spring support including
at least one fluid flow opening there through for fluid flowing
through the valve opening.
33. The by-pass valve of claim 32 wherein the housing defines in
the second bore a support surface for supporting the discrete
spring support about a periphery thereof.
34. The by-pass valve of claim 33 wherein the support surface
includes an annular seat about a periphery of the second bore.
35. The by-pass valve of claim 33 including a third bore in direct
communication with the second bore, the second bore communicating
directly with the first bore, the second bore having a larger
cross-sectional flow area than the third bore, wherein a peripheral
seat located at a transition between the second bore and the third
bore provides the support surface for supporting the discrete
spring support.
36. The by-pass valve of claim 33 wherein the spring support
includes a substantially planar disk having a plurality of flow
openings formed therethrough.
37. The by-pass valve of claim 33 wherein the spring support has a
cup-like profile, including an annular wall having an outer
peripheral flange at a first end thereof and a radially inwardly
extending flange at an opposite end thereof, the opposite end being
located further from the first bore than the first end thereof, the
peripheral flange engaging the support surface about the periphery
of the second bore, the second end of the return spring being
received within the annular wall and engaging the inwardly
extending flange, the at least one flow opening being defined by
the inwardly extending flange.
38. The by-pass port of claim 37 wherein the annular wall tapers
inward from the first end of the spring support to the opposite end
thereof and flow openings pass through the annular wall.
39. The by-pass port of claim 33 wherein the spring support has a
cup-like profile, including an annular wall having an outer
peripheral flange at a first end thereof and an annular spring seat
at an opposite end thereof, the opposite end being located closer
to the first bore than the first end thereof, the peripheral flange
engaging the support surface about the periphery of the second
bore, the second end of the return spring being received within the
spring seat.
40. The by-pass valve of claim 32 wherein the reciprocating seal
includes a reciprocating central shaft disposed along a central
axis of the first bore and having a closed end portion, and an
annular sealing member slidably mounted on the central shaft and
extending outward from the central shaft to engage the valve seat
and together with the closed end portion close the valve opening;
and the actuator includes bias means for urging the annular sealing
member toward the valve seat, the return spring having its first
end connected to the closed end portion.
41. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing defining first and second bores aligned along
a central axis and communicating through a valve opening surrounded
by a peripheral valve seat, the first bore, second bore and valve
opening forming at least a portion of a closable flow path between
a first opening and a second opening in the housing; a temperature
responsive actuator located in the first bore and having a
reciprocating central shaft disposed along said central axis, the
central shaft having a closed end portion; an annular sealing
member slidably mounted on the central shaft and extending outward
from the central shaft to engage the valve seat and, together with
the closed end portion, close the valve opening; bias means for
urging the annular sealing member toward the valve seat; and a
coiled return spring mounted in the housing for urging the central
shaft closed end portion to retract and open the valve opening, the
return spring having a first end connected to the closed end
portion and a second end engaging a spring support in the housing
facing the first bore, wherein the valve seat and the annular
sealing member have corresponding sloping surfaces that cooperate
when the sealing member engages the valve seat.
42. The by-pass valve of claim 41 wherein the corresponding sloping
surfaces include cooperating conical portions.
43. A by-pass valve for a heat exchanger circuit, the by-pass valve
comprising: a housing formed from a plastic material and defining a
first bore with a valve opening communicating therewith, the valve
opening having a peripheral valve seat facing the first bore, the
housing defining an assembly opening communicating with the first
bore opposite the valve seat, the first bore and valve opening
forming at least a portion of a closable flow path between a first
opening and a second opening in the housing; an actuator located in
the first bore and having a reciprocating seal disposed for
movement along an axis for engaging the valve seat and closing the
valve opening; and a closure cap formed from resilient material and
closing the assembly opening, the closure cap being sealably
mounted in an end of the upper bore adjacent the assembly opening,
the housing including surfaces between which the closure cap is
compressively engaged.
44. The by-pass valve of claim 43 wherein the housing and the
closure cap include adjacent tapering surfaces, at least one of the
tapering surfaces having an annular protrusion formed thereon for
engaging the other of the tapering surfaces.
45. The by-pass valve of claim 44 including a plurality of the
annular protrusions formed on the tapering surfaces.
Description
FIELD OF THE INVENTION
[0001] This invention relates to heat exchangers, and in
particular, to by-pass valves for by-passing a heat exchanger in a
heat exchange circuit under conditions where the heat transfer
function of the heat exchanger is not required or is only
intermittently required.
BACKGROUND
[0002] In certain applications, such as in the automotive industry,
heat exchangers are used to cool or heat certain fluids, such as
engine oil or transmission fluid or oil. In the case of
transmission fluid, for instance, a heat exchanger is used to cool
the transmission fluid. The heat exchanger is usually located
remote from the transmission and receives hot transmission oil from
the transmission through supply tubing, cools it, and delivers it
back to the transmission again through return tubing. However, when
the transmission is cold, such as at start-up conditions, the
transmission oil is very viscous and does not flow easily through
the heat exchanger, if at all. In such cases, the transmission can
be starved of oil and this may cause damage or at the least erratic
performance. Cumulative damage to the transmission can also occur
if the quantity of oil returned is adequate, but is overcooled due
to low ambient temperatures. In this case, for instance, moisture
condensation in the oil (that would otherwise be vaporized at
higher temperatures) may accumulate and cause corrosion damage or
oil degradation.
[0003] In order to overcome the cold flow starvation problem,
various solutions have been proposed in the past. One solution is
to use a by-pass path between the heat exchanger supply and return
lines often with a heat-actuated by-pass valve located in the
by-pass path. There have been short-comings with many prior
solutions, including for example, excessive leakage across the
valve, sticking of the valve, heat transfer inefficiencies, and/or
high cost.
[0004] A by-pass valve configuration that addresses many of the
short comings of prior actuator valves is shown in U.S. Pat. No.
6,253,837.
[0005] However a by-pass valve having additional cost savings,
space savings, weight savings and/or operational efficiencies is
desirable for some applications.
SUMMARY
[0006] According to at least one example aspect of the invention is
a heat exchanger by-pass, including a housing defining
communicating first and second bores therein and first and second
main ports communicating with the first bore, the second bore
having a central axis and a peripheral valve seat about a valve
opening facing the first bore. A temperature responsive actuator is
located in the housing and has a reciprocating central shaft
disposed along said central axis, the central shaft having a closed
end portion. An annular sealing member slidably mounted on the
central shaft extends outward from the central shaft to engage the
valve seat and, together with the closed end portion, close the
valve opening. The by-pass valve includes bias means for urging the
annular sealing member toward the valve seat A coiled return spring
is mounted in the housing for urging the central shaft closed end
portion to retract and open the valve opening, the return spring
having a first end connected to the closed end portion and a second
end engaging a spring support in the housing facing the first bore.
The return spring has a larger diameter at its second end than its
first end.
[0007] According to at least one example aspect of the invention is
a valve including a housing defining a first bore and a second bore
having a common central axis and communicating with each other
through a valve opening having a peripheral valve seat, the first
bore, second bore and valve opening forming at least a portion of a
closable flow path between a first opening and a second opening in
the housing. An actuator located in the housing has a reciprocating
seal disposed for movement along the central axis for engaging the
valve seat and closing the valve opening. A coiled return spring is
mounted in the housing for urging the reciprocating seal towards
the first bore to open the valve opening, the return spring having
a first end connected to the reciprocating seal and a second end
engaging a spring support in the housing facing the first bore, the
return spring having a larger diameter at its second end than its
first end.
[0008] According to at least one example aspect of the invention is
a by-pass valve for a heat exchanger circuit, including a housing
defining a serially communicating first bore, second bore and third
bore substantially aligned along a central axis with a valve seat
facing the first bore at a juncture between the first bore and
second bore and a spring seat facing the second bore at a juncture
between the second bore and third bore, the first bore, second bore
and third bore forming at least a portion of a closable flow path
between a first opening and a second opening in the housing. The
by-pass valve also includes an actuator located in the housing and
having a reciprocating seal disposed for movement along the central
axis for engaging the valve seat and closing a valve opening
between the first bore and second bore, and a coiled return spring
mounted in the housing for urging the reciprocating seal towards
the first bore to open the valve opening, the return spring having
a first end acting on the reciprocating seal and a second end
engaging the spring seat. The second bore and third bore each have
a different cross-sectional shape transverse to the central
axis.
[0009] According to at least one example aspect a by-pass valve for
a heat exchanger circuit, the by-pass valve including a housing
formed from plastic material and defining a first bore with a valve
opening communicating therewith, the valve opening having a
peripheral valve seat facing the first bore, the housing defining
an assembly opening communicating with the first bore opposite the
valve seat, an actuator located in the first bore and having a
reciprocating seal disposed for movement along an axis for engaging
the valve seat and closing the valve opening, and a closure cap
formed from plastic material and closing the assembly opening, the
closure cap being sealably joined to the housing by a permanent
joint.
[0010] According to at least one example aspect of the invention is
a method for making a by-pass valve for a heat exchanger circuit,
including: providing a housing defining a first bore with a valve
opening communicating therewith, the valve opening having a
peripheral valve seat facing the first bore, the housing including
an assembly opening opposite the valve seat; providing a closure
cap; providing an actuator having a reciprocating seal and
inserting the actuator into the first bore through the assembly
opening so that the actuator is located in the first bore for
movement along a central axis for engaging the valve seat and
closing the valve opening; and permanently connecting the closure
cap to the housing to seal the assembly opening.
[0011] According to at least one example aspect of the invention is
a by-pass valve for a heat exchanger circuit, the by-pass valve
including a housing defining a communicating first bore and second
bore with a peripheral valve seat located at a junction thereof
about a valve opening, the first bore, second bore and valve
opening forming at least a portion of a closable flow path between
a first opening and a second opening in the housing. The by-pass
valve includes an actuator located in the first bore and having a
reciprocating seal disposed for movement to engage the valve seat
and close the valve opening, a coiled return spring mounted in the
housing for urging the reciprocating seal towards the first bore to
open the valve opening, the return spring having a first end acting
on the reciprocating seal, and a second end. A discrete spring
support extends across the second bore and has a surface supporting
the second end of the return spring, the spring support including
at least one fluid flow opening there through for fluid flowing
through the valve opening.
[0012] According to at least one example aspect of the invention is
a by-pass valve for a heat exchanger circuit, the by-pass valve
including a housing defining first and second bores aligned along a
central axis and communicating through a valve opening surrounded
by a peripheral valve seat, the first bore, second bore and valve
opening forming at least a portion of a closable flow path between
a first opening and a second opening in the housing. The by-pass
valve also includes a temperature responsive actuator located in
the first bore and having a reciprocating central shaft disposed
along said central axis, the central shaft having a closed end
portion, an annular sealing member slidably mounted on the central
shaft and extending outward from the central shaft to engage the
valve seat and, together with the closed end portion, close the
valve opening, bias means for urging the annular sealing member
toward the valve seat, and a coiled return spring mounted in the
housing for urging the central shaft closed end portion to retract
and open the valve opening, the return spring having a first end
connected to the closed end portion and a second end engaging a
spring support in the housing facing the first bore. The valve seat
and the annular sealing member have corresponding sloping surfaces
that cooperate when the sealing member engages the valve seat.
[0013] According to at least one example aspect of the invention is
a by-pass valve for a heat exchanger circuit, the by-pass valve
including a housing formed from a plastic material and defining a
first bore with a valve opening communicating therewith, the valve
opening having a peripheral valve seat facing the first bore, the
housing defining an assembly opening communicating with the first
bore opposite the valve seat, the first bore and valve opening
forming at least a portion of a closable flow path between a first
opening and a second opening in the housing; an actuator located in
the first bore and having a reciprocating seal disposed for
movement along an axis for engaging the valve seat and closing the
valve opening; and a closure cap formed from resilient material and
closing the assembly opening, the closure cap being sealably
mounted in a end of the upper bore adjacent the assembly opening,
the housing including surfaces between which the closure cap is
compressively engaged.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Example embodiments of the invention will now be described
with reference to the accompanying drawings, throughout which
similar elements and features are denoted by the same reference
numbers, and in which:
[0015] FIG. 1 is an elevational view, partly in cross-section, of a
by-pass valve according to an example embodiment of the invention,
showing the by-pass valve in an open position;
[0016] FIG. 2 is an elevational view, partly in cross-section,
showing the by-pass valve in a closed position;
[0017] FIG. 3 is an elevational cross-section exploded view showing
a housing and closure cap of the by-pass valve of FIGS. 1 and
2;
[0018] FIG. 4 is an elevational view of a valve assembly used in
the by-pass valve of FIGS. 1 and 2;
[0019] FIGS. 5A-5D show views of a closure cap used in the by-pass
valve of FIGS. 1 and 2, wherein FIG. 5A is a perspective view, FIG.
5B is an elevational view, FIG. 5C is a bottom plan view, and FIG.
5D is a sectional view taken along the line A-A of FIG. 5C;
[0020] FIG. 6 is a sectional view of the housing, taken along the
line B-B of FIG. 3;
[0021] FIG. 7 is an elevational view, partly in cross-section, of a
by-pass valve according to a further example embodiment of the
invention, showing the by-pass valve in an open position;
[0022] FIG. 8 is an elevational view, in cross-section, of a
by-pass valve according to a further example embodiment of the
invention, showing the by-pass valve in an open position;
[0023] FIGS. 9A and 9B are plan views each showing an example of a
return spring support member for use in the by-pass valve of FIG.
8;
[0024] FIGS. 10 and 11 are elevational views, in cross-section,
each showing a further example of a return spring support member
for use in the by-pass valve of FIG. 8;
[0025] FIG. 12 is an elevational view, in cross-section, of a
by-pass valve having a valve sealing configuration according to a
further example embodiment of the invention, showing the by-pass
valve in an open position;
[0026] FIG. 13 is a plan view of an annular valve member used in
the by-pass valve sealing configuration of FIG. 12;
[0027] FIG. 14 is a sectional view of the annular valve member,
taken across lines C-C of FIG. 13;
[0028] FIG. 15 is an elevational view of a valve assembly having a
further embodiment of a return spring;
[0029] FIG. 16 is a partial sectional view of a further embodiment
of a cap received in an upper end of the by-pass valve housing;
and
[0030] FIG. 17 is an elevational view of the cap of FIG. 16.
DESCRIPTION OF EXAMPLE EMBODIMENTS
[0031] Referring firstly to FIG. 1, there is shown a by-pass valve,
indicated generally by reference 14. By-pass valve 14 may be used
in a heat exchanger circuit to control the flow a fluid to a heat
exchanger 12, to which first and second conduits 28 and 32 are
connected. Conduits 28, 32 are connected to inlet and outlet ports
in by-pass valve 14 as will be described further below. Conduits
34, 36 are also connected to ports in by-pass valve 14 as will be
described further below. By-pass valve 14 is referred to as a four
port by-pass valve, because four conduits 28, 32, 34 and 36 are
connected to by-pass valve 14.
[0032] Referring now to FIGS. 1-4, the by-pass valve 14 has a
housing 46 with serially communicating coaxial first bore 48,
second bore 54 and third bore 55 therein. In an example embodiment,
the housing 46 is formed of a moldable material such as a plastic
material which may be a thermoplastic or a thermosetting material
and which may contain reinforcement such as glass fiber or
particulate reinforcement. Housing 46 defines two main ports or
openings 50, 52 communicating with the first bore 48. Third bore 55
has a smaller cross-sectional flow area than that of second bore
54. First bore 48 communicates directly with second bore 54 which
in turn communicates through third bore 55 with two openings or
branch ports 56, 58. Conduits 28, 36 are connected respectively to
the branch ports 56, 58. Conduits 32 and 34 are connected to main
ports 50 and 52, respectively. Ports 50, 52, 56 and 58 may be
internally threaded for receiving threaded end portions of conduits
32, 34, 28 and 36, respectively, however the conduits and ports
could alternatively be connected using other methods, including for
example molding the ports around the conduits.
[0033] Second bore 54 has a peripheral valve seat 60 facing first
bore 48. In the illustrated embodiment, valve seat 60 is an annular
shoulder formed about valve opening 53 by housing 46 at a
transition or junction between first bore 48 and second bore 54. A
movable valve member 62 is adapted to engage valve seat 60 to open
and close valve opening 53. A temperature responsive actuator 64 is
located inside first bore 48 and is operably coupled to valve
member 62 to move valve member 62 thereby opening and closing valve
opening 53. Actuator 64 is sometimes referred to as a thermal motor
and it is a piston and cylinder type device wherein the cylinder is
filled with a thermal sensitive material, such as wax, that expands
and contracts causing the actuator to extend axially upon being
heated to a predetermined temperature.
[0034] It will be seen from FIGS. 1-4 that actuator 64 is located
along a central axis of first bore 48 and second bore 54. In an
example embodiment, coaxial first bore 48 and second bore 54 are
both generally cylindrical, with second bore 54 having a smaller
diameter than first bore 48. The cylinder of actuator 64 forms a
central shaft 66 disposed along the central axis of first bore 48
and second bore 54. Central shaft 66 has a closed end portion 68
that has a diameter less than that of second bore 54 and which
partially closes valve opening 53. Valve member 62, which is in the
form of an annular ring located adjacent to closed end portion 68
in its normal or at rest position as indicated in FIG. 1, extends
transversely from the central shaft 66 to engage valve seat 60 to
close valve opening 53 as indicated in FIG. 2. The annular ring 62
and closed end portion 68 form a reciprocating plug which moves
along the central axis to open and close valve opening 53. Annular
ring or valve member 62 is slidably mounted on central shaft
66.
[0035] Third bore 55, which is coaxial with first bore 48 and
second bore 54 has a different cross-sectional flow area than
second bore 54. In the presently described example embodiment, the
cross-sectional flow area of the third bore 55 is smaller than that
of the second bore 54, such that the housing 46 defines a
peripheral spring seat 69 facing the second bore and first bore 48
at a junction or transition between the second and third bores 54,
55. A return spring 70 has a first end 40 attached to closed end
portion 68 by being located in a groove (not shown) formed in
closed end portion 68. The return spring 70 has a second end 42
located in spring seat 69. Return spring 70 thus urges the central
shaft 66 away from valve seat 60 into its retracted position of
FIG. 1, and acts as a stop for preventing annular ring 62 from
sliding off central shaft 66. As best seen in FIG. 4, the return
spring 70 has a coil diameter that gets larger as the distance from
end portion 68 increases, such that the return spring 70 tapers
outward from first end 40 to the second end 42. In particular, the
spring coil diameter at first end 40 is sized to fit around closed
end portion 68, and the spring coil diameter at second end 42 is
sized about the same as the diameter of second bore 54.
[0036] As will be apparent from FIG. 4, thermal motor 64, override
spring 74, annular ring 62 and return spring 70 form a valve
cartridge or subassembly 38 for by-pass valve 14. As best seen in
FIG. 4, central shaft 66 includes an inner annular shoulder 72, and
a override spring 74 mounted on central shaft 66 between shoulder
72 and annular ring 62. The override spring 74 urges or biases
annular ring 62 toward the stop or return spring 70, and thus
toward valve seat 60.
[0037] As best seen in FIG. 3, the first bore 48 includes an
opening 81 that opposes valve opening 53 and through which the
valve assembly 38 of FIG. 4 can be inserted into first bore 48
during assembly of the by-pass valve 14. A closure cap 80 is
inserted into the opening 81 to seal the first bore 48 after the
valve assembly 38 is in place. As with housing 46, closure cap 80
may be formed from a moldable material such as a plastic material
which may be a thermoplastic or a thermosetting material and which
may contain reinforcement such as glass fiber or particulate
reinforcement. The closure cap 80 is in at least one example
embodiment ultrasonically welded to the housing 46 to form a secure
seal.
[0038] Thermal motor or actuator 64 has a piston 76 (see FIG. 4)
that is attached or fitted into an axial recess 78 (see FIG. 3)
formed in closure cap 80. As will be described in more detail
below, when thermal motor 64 reaches a predetermined temperature,
it extends axially. Since piston 76 is fixed in position, central
shaft 66, which is part of thermal motor 64, moves downwardly
through second bore 54 compressing return spring 70 and closing
valve opening 53. When the temperature inside first bore 48 drops
below the predetermined temperature, thermal motor 64 retracts and
return spring 70 urges central shaft 66 upwardly until return
spring 70 engages annular ring 62 and lifts it off valve seat 60
again opening valve opening 53. When valve opening 53 is opened as
indicated in FIG. 1, return spring 70 extends through second bore
54 and partially into first bore 48.
[0039] The operation of by-pass valve 14 will now be described with
reference to FIGS. 1-4. The heat exchange circuit in which the
valve 14 is used can be operated with either conduit 34 or conduit
36 being the inlet conduit, the other one being the outlet conduit.
Where conduit 34 is the inlet conduit, or in other words, receives
hot transmission oil from the transmission, this is sometimes
conveniently referred to as forward flow. In this case, conduit 36
is the outlet conduit and returns the transmission oil to the
transmission after it has been cooled by heat exchanger 12.
[0040] Where conduit 36 is the inlet conduit receiving the hot
transmission fluid or oil from the transmission and conduit 34 is
the outlet or return conduit for delivering the cooled oil back to
the transmission, this configuration is sometimes conveniently
referred to as reverse flow.
[0041] Dealing first with the forward flow configuration, if the
transmission oil and heat exchange circuit 10 have been warmed up
to operating temperatures, by-pass valve 14 appears as in FIG. 2.
Hot engine oil enters into inlet conduit 34, passes in series
through main port 52, first bore 48 and main port 50 to heat
exchanger inlet conduit 32. The hot fluid passes through heat
exchanger 12 and returns through outlet conduit 28, passes through
branch ports 56, 58 and out through outlet conduit 36 to return to
the transmission. In this case, there is substantially no by-pass
flow, because valve opening 53 is closed. If the fluid returning to
the transmission through conduits 28, 36 drops below a
predetermined temperature, by way of non-limiting example about 80
degrees C., actuator 64 retracts causing valve member 62 to lift
off valve seat 60 opening valve opening 53, as in FIG. 1. This
creates a by-pass flow from conduit 34 through first bore 48 and
through valve opening 53 to join the flow in conduit 36 returning
to the transmission. If the temperature of the flow or oil is very
cold, such as at engine start-up conditions, the oil may be so
viscous that virtually no flow goes through heat exchanger 12 and
the flow is totally by-passed from inlet conduit 34 to outlet
conduit 36. As the oil starts to warm up, however, flow through
conduit 32 and heat exchanger 12 starts to increase, and by the
time the oil reaches the desired operating temperature, full flow
is occurring through heat exchanger 12 and valve member 62 closes
valve opening 53 discontinuing the by-pass flow. It will be
appreciated that when by-pass valve 14, or at least valve member
62, is open main ports 52 and 50 become respective inlet and outlet
ports in this forward flow configuration. In the forward flow
configuration, one of the branch ports, namely branch port 56
becomes an inlet port, and the other branch port 58 thus becomes an
outlet port communicating with inlet port 56.
[0042] In the reverse flow configuration, conduit 36 becomes the
inlet conduit receiving hot oil from the transmission, and conduit
34 becomes the outlet conduit returning the cooled transmission oil
to the transmission. In this configuration, if the transmission and
heat exchange circuit 10 are at operating temperatures, the hot
transmission fluid passes through branch port 58, which becomes an
inlet port. Valve member 62 is closed so there is no by-pass flow.
The hot oil then continues on through branch port 56 which becomes
an outlet port communicating with inlet branch port 58. The hot oil
goes through conduit 28 and the heat exchanger 12 and returns
through conduit 32 to pass in series through second main port 50,
first bore 48 and third main port 52 and out through conduit 34 to
be returned to the transmission.
[0043] If the transmission oil returning to the transmission drops
below the predetermined temperature, actuator 64 causes valve
member 62 to open creating by-pass flow from valve opening 53 to
main port 52 and conduit 34. Again, if the oil is extremely cold,
such as at engine start-up conditions, very little, if any, flow
passes through heat exchanger 12 and there is almost total by-pass
through by-pass valve 14. As the transmission oil starts to warm
up, some flow starts to go through heat exchanger 12 and returns
through conduit 32 to first bore 48 and back to the transmission
through conduit 34. This causes actuator 64 to warm up faster than
would otherwise be the case. As the transmission oil returning to
the transmission through outlet conduit 34 reaches the
predetermined temperature, actuator 64 extends closing valve member
62 and stopping the by-pass flow. In this configuration, any
pressure peaks that might occur upon the closing of valve member 62
are attenuated or modulated, because valve member 62 can lift off
valve seat 60 by such a pressure surge, since valve member 62 is
urged into position by override spring 74 and not solidly in
engagement with valve seat 60. In other words, override spring 74
can absorb pressure spikes in inlet conduits 36, 28, so that they
do not travel back and adversely affect the transmission. The
circuiting of the valve is such that the housing functions as a
mixing chamber, in which the by-pass fluid stream and the heat
exchanger outlet stream can mix in direct contact with the thermal
actuator, so that thermal transients are damped, and the actuator
is able to directly respond to the mixed oil temperature being
returned to the transmission. Also during the transition between
opening and closing, the hot by-pass stream and cooler oil cooler
return stream are mixed (as controlled by the directing contacting
actuator 64) to dampen any temperature transients in the oil being
returned to the transmission.
[0044] In the reverse flow configuration, main ports 50, 52 become
respective inlet and outlet ports for by-pass valve 14.
[0045] As actuator 64 is located in first bore 48 with oil
continuously flowing therethrough, actuator 64 warms up and cools
off quickly. Also, if the transmission oil becomes over-heated or
experiences a temperature spike, actuator 64 is not damaged,
because it will normally be exposed to some return flow from heat
exchanger 12 in first bore 48 in the reverse flow configuration, or
in branch ports 56, 58 in the forward flow configuration. Further,
if actuator 64 is overheated and tends to expand too far, it will
not be damaged, because central shaft 66 can extend through second
bore 54 as required.
[0046] Having described the overall configuration and operation of
an example embodiment of the by-pass valve 14, particular features
of the by-pass valve will now be described in greater detail.
[0047] Turning to FIG. 3 and FIGS. 5A-5C, in the illustrated
embodiment, cap 80 defines an outer cylindrical wall 90 sized to
fit in the upper end of first bore 48, and a larger diameter
disk-like head 92. First bore 48 has a cap seat 94 formed about a
circumference of opening 81 in which enlarged cap head 92 is
located. As illustrated, the axial recess 78 (which receives an end
of thermal motor piston 76) is defined by an inner cylindrical wall
96 that is radially spaced from external cylindrical wall 90. A
series of uniformly spaced radial webs 100 extend between inner and
outer walls 96, 90. An annular groove 102 (FIG. 5B) may be formed
in an outer surface of the outer cylindrical wall 90. As noted
above, cap 80 can be ultrasonically welded to housing 46 in order
to seal the opening 81 of first bore 48, providing a light weight,
inexpensive and durable means for sealably closing assembly opening
81 of the first bore 48 which, in at least some applications, will
not require an additional seal such as an O-ring, and/or will not
require an addition retaining member such as a C-clip. Although the
presently described cap provides certain advantages, in some
embodiments plastic cap 80 could be replaced with a metal cap
having an annular sealing ring, and/or could be secured in place
through some other non-permanent means such as, for example, with a
C-clip, or by being threaded, or having a twist lock configuration,
rather than through ultrasonic welding. Furthermore, a permanent
leak resistant joint between the cap 80 and housing 46 could be
formed by methods other than ultrasonic welding, such as by
friction welding, or through chemical bonding. Chemical bonding
could include the use of an intermediate adhesive or solvent
bonding in which a solvent is used to temporarily disolve
cooperating surfaces that then join together, thereby providing a
bonding effect similar to ultrasonic or friction welding.
Additionally, the cap 80 may be used with housing and valve
assembly combinations that are different from that shown in the
Figures and described herein.
[0048] With reference to FIGS. 3 and 6, third bore 55 will now be
discussed in greater detail. As indicated above, the second bore 54
communicates with branch ports 56 and 58 through third bore 55,
with peripheral spring seat 69 facing second bore 54. The third
bore 55 in combination with peripheral spring seat 69, allows the
return spring 70 to be supported above the internal passage through
housing 46 that is provided by cooperating and coaxial branch ports
56 and 58, thereby providing unimpeded flow between the branch
ports 56 and 58. Spring seat 69 is defined by housing 48 as a
result of the reduction in cross-sectional flow area between the
second bore 54 and the third bore 55. As noted above, second bore
54 is cylindrical, and thus has a circular cross-sectional flow
area transverse to its axis. In an example embodiment, the third
bore 55 has a non-circular cross-sectional flow area, and in
particular, as seen in FIG. 6, the third bore 55 has a rectangular
cross-sectional area along its length. Thus, the size of the spring
seat 69 varies about the periphery of the third bore 55. The use of
a third bore 55 having a non-circular cross-section allows the flow
area of the third bore 55 to be maximized, while at the same time
providing a stable seat 69 for return spring 70. Such a
non-circular configuration may be particularly advantageous in
embodiments where the coil diameter of the return spring 70 does
not increase towards the spring seat 69, in which case a spring
seat extending further inward from the outer circumference of the
wall defining second bore 54 would be required. Instead of being
rectangular, other non-circular cross-sectional configurations
could be used, for example other multi-sided configurations such as
square or polygon, or curved configurations such as elliptical,
could be employed.
[0049] In some embodiments, third bore 55 may be cylindrical with a
circular cross-sectional area. For example, when third bore 55 is
used in combination with an outwardly tapering return spring 70, in
some applications a non-circular third bore 55 may not offer that
substantial an advantage over a circular third bore 55. However, in
other applications, the increased flow permitted by a non-circular
third bore 55 may be highly advantageous.
[0050] In some embodiments, spring seat 69 may be provided by means
other than a transition between second bore 54 and a cooperating
coaxial third bore 55. For example, the second and third bores
could be replaced with a single bore having a substantially uniform
diameter along its entire length, and spring seat 69 could be
accomplished by an inwardly extending ring formed on the wall of
the bore 54 or 55 about opening 53, or by other inward projections
formed on the wall of the bore 54 or 55.
[0051] With reference again to FIGS. 1-4, tapered return spring 70
will now be discussed in greater detail. As will be appreciated
from the above description, the piston or central shaft 66 of valve
assembly 38 has a smaller diameter than second bore 54 so that
closed end portion 68 can extend into second bore 54, and also to
facilitate fluid flow around the shaft 66 when valve member 62 is
not in valve seat 60. Thus, the first end 40 of return spring 70
that is attached to end portion 68 will also have a smaller
diameter than the second bore 54. As indicated above, the diameter
of the successive coils of the return spring 70 increase from the
first end 40 to the seat engaging second end 42, such that the
diameter of the second end 42 is substantially the same as or close
to the inner diameter of second bore 54. Such a spring
configuration can provide a number of advantages. For example,
having a second end 42 diameter that is the same or close to the
same size as the second bore diameter provides a self-centering and
self locating feature and assists in positioning the spring in the
valve opening 53 and maintaining the second end 42 in correct
alignment with spring seat 69, thereby allowing a smaller spring
seat 69 (and hence larger third bore 55) to be used than might
otherwise be required if a return spring of uniform coil size were
employed. The spring 70 may also assist in centering the valve
assembly 38, including valve member 62, during operation of the
by-pass valve. Additionally, the use of a spring of varying coil
diameter allows for a greater distance between adjacent coils as
the coils expand, as adjacent coils are not only axially spaced
from each other (as in a uniform diameter spring), but are also
radially spaced from each other. Thus, there is increased area for
fluid to flow through the coils of the tapered return spring 70
such that spring 70 offers less flow resistance than a similar
non-tapered return spring.
[0052] In some embodiments, as has been suggested above and will be
explained below, a spring of uniform diameter may be used in place
of tapered spring 70. Additionally, in some embodiments, the
tapered return spring 70 may be used in combination with a by-pass
valve having features other than those described above. For
example, FIG. 7 shows a further example embodiment of an open
by-pass valve 110, in which tapering return spring 70 may be used.
The by-pass valve 110 is similar in configuration and operation to
by-pass valve 14, with differences that will be apparent from the
Figures and present description. By-pass valve 110 is a two-bore
design in that the third bore 55 is omitted. The second bore 54
communicates directly with a branch port flow passage 112 formed by
coaxial and cooperating branch ports 56, 58. The valve seat 69 and
valve opening 53 are located at the juncture between first bore 48
and second bore 54. In such embodiment, the return spring 70
extends across passage 112 and its second end 42 rests against a
wall 114 of branch port flow passage 112 that faces the first bore
48 and valve opening 53. In such configuration, the tapering spring
70 offers less flow resistance in passage 112 than a uniform
diameter spring would.
[0053] Turning again to the by-pass valve configuration of FIGS.
1-4, in some embodiments branch ports 58 and 56 may be omitted, and
the third bore 55 may communicate directly with one of the conduits
28 or 36, in which case the by-pass valve would be a three port
valve, with third bore 55 being an inlet or outlet port to the
by-pass valve. In such a configuration, whichever of the conduits
28 or 36 is not connected to communicate with third bore 55 will be
connected to the other conduit 28 or 36 at a location spaced apart
from the by-pass valve.
[0054] As noted above, in some embodiments a uniform coil return
spring may be used in place of a tapered return spring 70, and in
this regard reference is now made to FIG. 8 which shows a further
example embodiment of an open by-pass valve 120, in which a
straight return spring 124 is used. The by-pass valve 120 is
similar in configuration and operation to by-pass valve 14, with
differences that will be apparent from the Figures and present
description. In the present embodiment, the extending end of the
uniform width return spring 124 is smaller than the third bore 55
that communicates with second bore 54, and thus a discrete spring
support member 122, examples of which are shown in plan view in
FIGS. 9A and 9B, is positioned in peripheral seat 69. Discrete
support member 122, which may be formed from metal or plastic
and/or other materials, is formed separately from housing 46 and
positioned on seat 69. In some example embodiments, the support
member 122 may be connected to the extending end of return spring
124 prior to the insertion of valve assembly 38 into the first bore
48. When the valve is assembled, the extending end of return spring
124 rests against the spring support member 122, and the other end
of the return spring engages end portion 68 of thermal motor shaft
66. Spring support member 122 can be a circular planar disk-like
member with a series of flow openings 126 formed therethrough.
Support member 122 could take a number of different configurations
to fulfill its dual function of supporting spring 124 while
allowing fluid to flow through the support member, with FIGS. 9A
and 9B showing but two possibilities. In the by-pass valve
configuration of FIG. 8, support member 122 allows third bore 55 to
be larger than if the uniform width return spring 124 rested
directly on seat 69 without the support member. In some example
embodiments, support member 122 may be used in combination with a
tapering return spring 70.
[0055] In at least one example embodiment, planar support member
122 is replaced with a cup-like support member 122A, as shown in
FIG. 10. Support member 122A includes an annular wall 130 having an
outer peripheral flange 128 at one end thereof and a radially
inwardly extending flange 132 at an opposite end thereof. The outer
flange 128 sits on seat 69, the annular wall 130 extends into third
bore 55, and return spring 124 is seated on inner flange 132. An
axial flow opening 126 is defined by flange 132. Annular wall 130
may be cylidrical, or may taper inwards as the distance from seat
69 increases. In some embodiments, particularly in tapering
embodiments, flow openings 134 may extend through the annular wall
130.
[0056] In some embodiments, a further cup-like support member 122B,
having a configuration substantially opposite that of support
member 122A, is used in combination with seat 69 to support the
return spring 124. Support member 122B includes an annular wall 136
having an outer peripheral flange 138 at one end and a shoulder
defining a spring seat 140 at an opposite end thereof. In use, the
outer peripheral flange 138 rests on seat 69, the annular wall 136
extends into the second bore 54 and the second end 42 of return
spring 124 rests in seat 140. The cup configurations 122A and 122B
assist in locating and retaining return spring 124.
[0057] Turning now to FIGS. 12-13 a further valve seat and valve
member combination that can be applied to any of the by-pass valves
described above will now be explained in the context of by-pass
valve 120. In FIG. 12, the annular valve member 62 and it
cooperating valve seat 68 have been modified, the modified elements
being denoted by 62' and 68', respectively. The valve seat 68',
formed about the periphery of an end of second bore 54 facing the
first bore 48, has an inwardly tapering profile. Similarly, annular
valve member 62', which in one example embodiment is formed from a
plastic material, has a tapering outer surface facing valve seat
68'. Thus, valve seat 68' and valve member 62' have corresponding
opposing truncated-conical or frusta-conical surfaces that
cooperate when in the closed position to seal valve first bore 48
from valve opening 53. The use of sloping or tapering engagement
surfaces provides a larger engagement interfaces between valve
member 62' and valve seat 68' than if the engagement surfaces are
simply at right angles to the first bore and valve opening axes.
The valve member 62' defines an axial cylindrical opening 146
through which thermal motor shaft 66 passes. In an example
embodiment, a lip or flange 148 is provided about a periphery of
the opening 146 on a side thereof that faces away from the second
bore 54, thereby providing a longer interface between member 62'
and shaft 66, making it more difficult for fluid to leak between
shaft 66 and valve member 62'. Valve member 62' and 68' may provide
an improved seal in some applications. The relatively large
internal surface that defines opening 146 provides a large contact
area along shaft 66, reducing the chance for binding of the sealing
valve member 62 as it moves along the shaft.
[0058] Turning again to the example embodiment of the by-pass valve
shown in FIGS. 1-4 and 7, although the return spring 70 has been
shown as having coils that continuously increase in diameter from
the first end 40 to the second end 42 of the spring 70, in some
example embodiments the coil diameter does not steadily increase
from the first end to the second end. By way of example, FIG. 15
shows an alternative return spring 70' that is used with valve
assembly 38 in some example embodiments. As indicated by dashed
line 150, the return spring 70' has an hourglass shape in that as
the axial distance increases from the first end 40, the coil
diameters first get smaller and then increases in size to the
second end 42 of the return spring 70'. Thus, along a first axial
length of the return spring 70', coils of the return spring 70'
have decreasing diameters as the distance of the coils from the
first end 40 increases, and along a second axial length of the
return spring 70' that is further from the first end 40 than the
first axial length, coils of the return spring 70' have increasing
diameters as the distance of the coils from the first end 40
increases. Such a configuration can in some applications facilitate
the flow of oil through the spring coils with reduced flow
resistance, especially high viscosity oil at low temperatures, and
also facilitate the passage of oil through the coils at higher
temperature when actuation of the thermal element causes the spring
70' to compress.
[0059] FIGS. 16 and 17 show another cap configuration for closing
the assembly opening 81 in housing 46. The cap 160, which may be
used in any of the above described configurations, is formed from a
resilient material (which can be plastic), such that cap 160 can be
inserted, with some radial compression occurring to it, through the
assembly opening 81 in the housing 46. Thus, the opening 81 has a
smaller diameter than the cap 160. FIG. 16 shows the cap 160 in a
first position "A" in which the cap 160 is just starting to be
inserted through opening 81, and in a second position "B" in which
the cap 160 is inserted into an upper end of the first bore 48.
[0060] The upper end of first bore 48 includes an annular recess
162 into which at least a portion of the cap 160 expands once the
cap has been inserted into place. Once inserted, the cap 160 is
effectively permanently locked in place. The recess 162 terminates
at an upper annular shoulder or seat 164. At a lower end, the
recess 162 has an inwardly tapering annular wall 166 that opposes
seat 164 at an oblique angle. The cap 160 has an upper surface 168
for engaging seat 164. The cap 160 has an upper cylindrical portion
170 which is received within recess 162, and has a lower tapering
annular wall portion 172 for engaging the wall 166 of recess 162.
Once the cap 160 is inserted into position, its upper surface 168
engages seat 168 and its lower tapering wall portion 172 engages
correspondingly tapered recess wall 166, thus placing the cap 160
under axial loading to prevent movement of it relative to housing
46. In an example embodiment, the cap 160 is sufficiently preloaded
(i.e. compressed between surfaces 164 and 166) after insertion such
that its stays secure throughout various temperature variation and
other stresses that occur during use and the lifespan of the valve.
In some embodiments, cap 160 may include one or more annular
protrusions or beads 174 formed on tapering portion 172 for
providing further sealing between the cap 160 and housing 46.
Alternatively, one or more annular beads 174 could be located on
the wall 166 in addition to or instead of on portion 172. In one
example embodiment, one annular bead 174 is located on portion
172.
[0061] Having described example embodiments of the invention, it
will be appreciated that various modifications in addition to those
already set forth can be made to the structures described above.
For example, in some embodiments either both or one or the other of
the housing and cap could be made of materials other than plastic
such as metal. A number of features have been described above, and
different features and combinations of features may be used in
different embodiments.
[0062] The by-pass valves have been described above for use with an
automotive transmission oil cooler as the heat exchanger, but the
by-pass valves could be used with any other types of heat
exchanger, such as fuel cooling heat exchangers, and in
non-automotive applications as well. Other types of thermal
actuators can be used than the wax-type actuator 64. For instances,
bimetallic or shape memory alloy thermal responsive actuators could
be used to move valve member. Further modifications to the
structures described will be apparent to those skilled in the
art.
[0063] As will be apparent to those skilled in the art in the light
of the foregoing disclosure, many alterations and modifications are
possible in the practice of this invention. Accordingly, the scope
of the invention is to be construed in accordance with the
substance defined by the following claims.
* * * * *